The present invention relates generally to a data copying method for a disk storage medium, and more particularly to a method of copying or recording a data recorded in a master disk storage medium onto a slave disk storage medium, the master disk storage medium having a number of unrecorded tracks and a number of recorded tracks in a mixed fashion, the slave disk storage medium having unrecorded tracks only.
Conventionally, there are several kinds of disk storage media (especially, a video disk) which are commonly used to store and record picture information or sound information. In most of such disk storage media, the information is recorded continuously in recording areas from an inner track of the disk to an outer track thereof. However, in a case of a certain disk storage medium, a recording area of the disk storage medium is divided into a plurality of tracks and a disk management data concerning how such disk tracks are assigned in the disk storage medium is already recorded onto a predetermined part of the disk storage medium in a manufacturing stage. For this reason, some recorded tracks may not appear in a successive manner, and recorded tracks and unrecorded tracks often exist in a maixed manner in the disk storage medium.
Usually, a backup disk is prepared as a master disk for storing important information for the users. And, there is a case in which it is required to prepare another backup disk which is a duplicate one of the original backup disk and has exactly the same arrangement of recorded tracks as that of the original backup disk in which recorded tracks and unrecorded tracks exist in a mixed fashion. In such a case, a recording of such important information is made from a master disk storage medium to a slave disk storage medium. In the master disk storage medium, the information is recorded onto a number of tracks at random, and in the slave disk storage medium no information is yet recorded (but, some disk control data concerning track addresses has already recorded in a manufacturing stage). A conceivable method of copying data in this case is to reproduce the information from the master disk storage medium by means of a reproducing unit, and to record a reproduced signal by the reproducing unit onto the slave disk storage medium. However, the reproducing unit usually outputs a signal at a specified level when a reproducing of the data is made at unrecorded tracks of the master disk storage medium. Thus, in a case of this data copying method, there is a problem in that such undesired data is also recorded to tracks of the slave disk storage medium corresponding to the unrecorded tracks of the master disk storage medium. If the slave disk storage medium is a magnetic disk or an erasable optical disk, the undesired data can be deleted later by checking the tracks of the disk where the undesired data is recorded and making a deletion of the undesired data. But, this is inconvenient to the users and additional work must be carried out. If the slave disk storage medium is another type of a recording disk which may be, for example, an addition-recording disk storage medium, it is difficult to produce a duplicate disk having the same track pattern as that of the master disk storage medium.